Investigators are still looking for a motive in relation to the Las Vegas shooting that left 58 people dead and hundreds injured, but that shooter is believed to have acted alone.

In an update provided by officials Friday, Clark County Sheriff Joe Lombardo said he “knows and believes” the shooter, 64-year-old Stephen Paddock, is the sole person responsible for what’s been deemed the worst shooting in U.S. history.

Officials said Paddock was perched on the 32nd floor of a Las Vegas hotel-casino on Oct. 1 when he unleashed a hail of bullets on an outdoor country music festival below as tens of thousands of concertgoers screamed and ran for their lives.

Police responded and a SWAT team broke into his room to find the gunman dead of suspected self-inflicted injuries

In news conference, Lombardo said that possible motive for the shooting was Paddock's loss of a "significant amount of wealth" prior to shooting. Also said disturbing search history found on Paddock's computer, incl. child porn.

Shortly after the shooting, Paddock’s brother, Eric Paddock, who lives in Florida, told the Orlando Sentinel: “We are completely dumbfounded. We can’t understand what happened.”

Investigators said they were looking into other suspects that could have been in some way involved in the mass-shooting, including Paddock’s girlfriend Marilou Danley.

On Friday, Lombardo announced Danley will not be facing any charges. Lombardo also said there is one person who is of “federal interest” and that charges could be filed in relation to that person, but did not elaborate on further details.